One of the images from the Boston manhunt sent to USA TODAY on Friday. Reader's post: "Feels like its straight out of a movie." / Hov Aroyian, Instagram

by Sharon Jayson, USA TODAY

by Sharon Jayson, USA TODAY

Bombings and suspects on the loose caused a lockdown in a major metropolitan area in the Northeast; fire and explosions rocked a small town in Texas.

But despite the distance and size of each community, today's ubiquitous video tools make it easy for everyone to share what they've seen. Even when told to stay away from these dangerous spots, people still can't seem to heed the warnings, often chronicling in real time with smartphone in hand and eager to post on YouTube or Instagram.

So why do ordinary people congregate at potentially risky places? Social psychologists say don't blame social media. Thrill-seekers aren't new. It's part curiosity and part sensation-seeking. But they say social media has changed the way many behave. It's created a "participant culture," says social psychologist Karen North, a professor of social media at the University of Southern California-Los Angeles.

"People want to say, 'I am the person who put up that video. I created that,' " she says. "They get reinforced in true psychological reward-and-punishment sense when people hit 'Like' or 'Share' or 'Comment.' "

North says there's a "competition motivation" as well - people compete to get close enough to take a picture or video worthy of an audience. In the past, people were more passive about the communication. Now, everyone wants to be active participants, she says.

"The tools of social media allow us to be content creators. It means we all can put our own creative products out there for other people to watch, listen to and interact with," she says.

Social psychologist Robert Kraut of Carnegie Mellon University in Pittsburgh likens the behavior to the "emergency equivalent of rubbernecking."

"People stop for accidents and look whether or not they're taking videos," he says.

Marvin Zuckerman of Philadelphia, a professor emeritus of psychology at the University of Delaware has written three books about "sensation-seeking." He says common sense isn't the issue here. Rather, it's about a balance.

"Life is a balance between potential reward and risk," he says. "Some people seem to be strong on the reward and weak on the risk side. High sensation-seekers tend to underestimate risk, and low sensation-seekers overestimate risk."

Even though the fertilizer plant in West, Texas, was burning on Wednesday night, people headed toward the fire to capture the scene. Videos on news sites show people nearby knocked over by the force of the explosion. Some were interviewed, and their videos shown, on national television.

And, despite warnings to stay indoors during Friday's police manhunt for Boston's fugitive bomber, some people wandered their neighborhoods to see what was happening.

"Even when people get official warnings and alerts from authoritative sources, such as a hurricane is coming and they should evacuate, they typically mill around to try and understand more what's going on, " Kraut says. "They're seeking social consensus - what the nature of the situation is and how they should respond. Before people actually take the advice, they want social validation."

The public may also be getting a bit of a mixed message. Just a few days earlier, after the Boston Marathon bombing, officials asked for video from the public to help find suspects.

"We've always turned to the public. There used to be wanted posters and pictures of missing children on milk cartoons. There's America's Most Wanted and Amber alerts on the freeway," North says. "They're using the wisdom or knowledge of the masses. Put it out there and see who can solve this problem. Instead of just having detectives or investigators and eye witnesses, they throw it out to everybody. Here's our puzzle. Help us solve it."